1. Field of the Invention
The present invention relates to an integral microphone and speaker configuration type communication apparatus suitable for use for example when a plurality of conference participants in two conference rooms hold a conference by voice. More particularly, the present invention relates to an integral microphone and speaker configuration type communication apparatus where the communication apparatus is used for equalizing acoustic couplings of a speaker and a plurality of microphones.
2. Description of the Related Art
A TV conference system has been used to enable conference participants in two conference rooms at distant locations to hold a conference. A TV conference system captures images of the conference participants in the conference rooms by imaging means, picks up their voices by microphones, sends the images captured by the imaging means and the voices picked up by the microphones through a communication channel, displays the captured images on display units of television receivers of the conference rooms of the other parties, and outputs the picked up voices from speakers.
In such a TV conference system, there is the problem that in each conference room, it is difficult to pick up the voices of the speaking parties at positions distant from the imaging means and the microphones. As a means for dealing with this, sometimes a microphone is provided for each conference participant. Further, there is also the problem that the voices output from the speakers of the television receivers are hard for conference participants at positions distant from the speakers to hear.
Japanese Unexamined Patent Publication (Kokai) No. 2003-87887 and Japanese Unexamined Patent Publication (Kokai) No. 2003-87890 disclose, in addition to a usual TV conference system providing video and audio for TV conferences in conference rooms at distant locations, a voice input/output system integrally configured by microphones and speakers having the advantages that the voices of conference participants in the conference rooms of the other parties can be clearly heard from the speakers and there is little effect from noise in the individual conference rooms or the load of echo cancellers is light.
For example, the voice input/output system disclosed in Japanese Unexamined Patent Publication (Kokai) No. 2003-87887, as described by referring to FIG. 5 to FIG. 8, FIG. 9, and FIG. 23 of that publication, is structured, from the bottom to the top, by a speaker box 5 having a built-in speaker 6, a conical reflection plate 4 radially opening upward for diffusing sound, a sound blocking plate 3, and a plurality of single directivity microphones (four in FIG. 6 and FIG. 7 and six in FIG. 23) supported by poles 8 in a horizontal plane radially at equal angles. The sound blocking plate 3 is for blocking sound from the lower speaker 5 from entering the plurality of microphones.
The voice input/output system disclosed in Japanese Unexamined Patent Publication (Kokai) Nos. 2003-87887 and 2003-87890 is utilized as means for supplementing a TV conference system for providing video and audio. As a remote conference system, however, often a complex apparatus such as a TV conference system does not have to be used: voice alone is sufficient. For example, when a plurality of conference participants hold a conference between a head office and a distant sales office of the same company, since everyone knows what everyone looks like and understands who is speaking by their voices, the conference can be sufficiently held, without the video of a TV conference system, just like speaking by phone. Further, when introducing a TV conference system, there are the disadvantages such as the large investment for introducing the TV conference system per se, the complexity of the operation, and the large communication costs for transmitting the captured video.
If assuming the case of application to such a conference using only audio, the voice input/output system disclosed in Japanese Unexamined Patent Publication (Kokai) No. 2003-87887 and Japanese Unexamined Patent Publication (Kokai) No. 2003-87890 can be improved in many ways from the viewpoint of the performance, the viewpoint of the price, the viewpoint of the dimensions, and the viewpoints of suitability with the usage environment, user-friendliness, etc.